Production methods and packaging requirements of t

Cheese production methods and packaging requirements

the cheese manufacturing industry was originally a seasonal industry. In many areas dealing with dairy products, the remaining part of fresh milk is processed into cheese in summer. The manufacturing process of cheese is mainly coagulation, slitting, heating to form curd, and then pressing, fermentation and removal of whey. The whole process is a microbial transformation process. In this process, enzymes produced by bacteria make cheese give off an attractive flavor and form its unique tissue

cheese is produced by rapid pasteurization of fresh milk (70 ℃ for a few seconds or 66 ℃ for 15 seconds). Then add a starter (Streptococcus), and the sugar and lactose in fresh milk begin to turn into lactic acid. When the appropriate acid value is reached, rennet is added to denature the milk protein and produce a "clot". Cut the clot into pieces and dry it by steam scalding. The temperature of the steam depends on the proportion of the milk produced to the exports of emerging countries, which will also greatly increase the cool types. Scalding method can make cheese particles shrink and condense and squeeze the clot dry. Acidity, temperature and freshness of cheese all accelerate the formation of clots. The clots sink to the bottom of the barrel, pile up with each other, and the precipitated whey flows out of the bottom of the barrel. Chymosin, acid and hot olives change Kuin, and the clot changes from rubber to dough. Cut the clot into small pieces, add salt to dissolve some proteins, help kneading, and properly control the activity of bacteria during ripening. Press a small piece of curd into the mold and dry it to make cheese. Finally, turn the cheese over, wash, add oil and wrap it, and put it into storage to ripen it. The taste and variety of cheese depend on the manufacturing process and the selected fermentation bacteria

the packaging and storage conditions of cheese have a great impact on its shelf life. General cheese has common requirements for packaging. First, oxygen must be isolated to prevent mildew and deterioration; Second, maintain water to maintain its flexible tissue and avoid weight loss. Generally speaking, the higher the water content of cheese, the easier it is to deteriorate and decay. Mold, such as Penicillium, is an important factor in the deterioration of cheese, and often appears in the cracks and pores on the surface of cheese. Cheese skin is generally not too dry, so it is easy to mold. Although under low temperature storage conditions, the acid value in cheese is not medium to resist mold growth. Although under low temperature storage conditions, the acid value in cheese is not enough to resist the growth of Qin bacteria. Soft cheese and cream cheese with high water content are very vulnerable to yeast and mold attack and deterioration. Cheese is usually packaged in aluminum foil with heat sealing coating on the inner surface. Since the microorganisms that cause cheese deterioration are aerobic bacteria, cheese should be packaged with oxygen barrier. If vacuum and sealed packaging filled with inert protective gas are used, the protection effect is better. These packaging methods have been used commercially. The general requirements of cheese for wrapping with plastic film are as follows

(L) mechanical strength

the mechanical strength of packaging materials should be considered in combination with the requirements of sealing methods and batch packaging

(2) non toxic

packaging materials must adapt to the characteristics of the product, and the transfer and pollution of harmful ingredients to the product are not allowed

(3) moisture control

the water vapor transmission rate of packaging materials should be low to prevent cheese from losing moisture in storage (for example, hard "Cheddar" cheese produced in Switzerland, in which the moisture content is 38%. The manufacturer stipulates that the water dispersion loss in the first month of delivery should be 4%, and then the monthly water dispersion loss in the aging process should be 1%

(4) oxygen permeability

in order to prevent mildew, the oxygen inside the package must be controlled at a very low limit. Therefore, the oxygen permeability of packaging materials should be very low. In actual production, the sealing effect of packaging is more important than 2. When clamping the sample, the upper jaw is fixed with a retainer, and the oxygen permeability of the packaging material is more important

(5) carbon dioxide transmittance

almost all living microorganisms will release carbon dioxide. However, for the processed hard cheese, the microbial flora emits very little carbon dioxide, part of which is dissolved in water and part of which is lost. In some cases, some fermenting bacteria can release a large amount of carbon dioxide gas in a short time, and the sealed packaging cannot pass through carbon dioxide, which may cause perforation of the packaging film and even swelling (swelling) phenomenon. However, in fact, there is a part of carbon dioxide inside the package, which can effectively inhibit the growth of most microorganisms and help prevent moldy cheese. Therefore, the cultivation material should have appropriate carbon dioxide transmittance

the packaging materials of cheese are generally polyethylene, polyvinyl chloride, ethylene copolymer, polyvinylidene chloride, polyamide, plastic coated fiber materials, aluminum foil and various plastic coated paper products. Heat shrinkable film packaging cheese can adapt to different shapes of products, and tightly wrap the products, eliminating the excess air inside the package. The bag made of materials with low air permeability among the above materials and vacuum packaging has a good protective effect on the quality of cheese. He designed three futures for the graphene industry: carbon fiber, which has been officially applied in actual production

reprinted from: Food Forum